Multiple-output dual-polarity DC/DC converters and voltage regulators

Abstract

A multi-output dual polarity inductive boost converter includes an inductor, a first output node, a second output node, and a switching network, the switching network configured to provide the following modes of circuit operation: a first mode where the positive electrode of the inductor is connected to an input voltage and the negative electrode of the inductor is connected to ground; 2) a second mode the negative electrode of the inductor is connected to ground and the positive electrode of the inductor is connected in sequence to one or more of the fourth and fifth output nodes; and 3) a third mode where the positive electrode of the inductor is connected to the input voltage and the negative electrode of the inductor is connected in sequence to one or more of the first, second and third output nodes.

What is claimed is: 
     
       1. A dual-polarity multi-output synchronous boost converter comprising:
 an inductor; 
 first, second, third, fourth and fifth output nodes; and 
 a switching network, the switching network being configured to provide a first mode of circuit operation in which a positive electrode of the inductor is connected to an input voltage and a negative electrode of the inductor is connected to ground, a second mode of circuit operation in which the negative electrode of the inductor is connected in sequence to each of the first, second and third output nodes and the positive electrode of the inductor is connected in sequence to each of the fourth and fifth output nodes, and a third mode of circuit operation in which the positive electrode of the inductor is connected to the input voltage and the negative electrode of the inductor is connected in sequence to each of the first, second and third output nodes. 
 
     
     
       2. The dual-polarity dual-output synchronous boost converter of  claim 1  further comprising a control circuit that causes the first, second and third modes to be selected in a repeating sequence. 
     
     
       3. The dual-polarity dual-output synchronous boost converter of  claim 2  wherein the repeating sequence has the form first mode, second mode, first mode, third mode. 
     
     
       4. The dual-polarity dual-output synchronous boost converter of  claim 3  wherein the repeating sequence has the form first mode, second mode, third mode. 
     
     
       5. The dual-polarity dual-output synchronous boost converter of  claim 1  further comprising a feedback circuit that modulates the duration of the respective connections between the inductor, the input voltage, ground and the output nodes to control the voltage of the output nodes. 
     
     
       6. The dual-polarity dual-output synchronous boost converter of  claim 1  wherein the switching network is configured to provide a fourth mode in which the negative electrode of the inductor is connected in sequence to one or more of the first, second and third output nodes and the positive electrode of the inductor is connected in sequence to one or more of the fourth and fifth output nodes. 
     
     
       7. A dual-polarity multi-output synchronous boost converter comprising:
 an inductor; 
 first, second, third, fourth and fifth output nodes; and 
 a switching network, the switching network being configured to provide a first mode of circuit operation in which a positive electrode of the inductor is connected to an input voltage and a negative electrode of the inductor is connected to ground, a second mode of circuit operation in which the negative electrode of the inductor is connected to ground and the positive electrode of the inductor is connected in sequence to each of the fourth and fifth output nodes, and-a third mode of circuit operation in which the positive electrode of the inductor is connected to the input voltage and the negative electrode of the inductor is connected in sequence to each of the first, second and third output nodes. 
 
     
     
       8. The dual-polarity dual-output synchronous boost converter of  claim 7  further comprising a control circuit that causes the first, second and third modes to be selected in a repeating sequence. 
     
     
       9. The dual-polarity dual-output synchronous boost converter of  claim 8  wherein the repeating sequence has the form first mode, second mode, first mode, third mode. 
     
     
       10. The dual-polarity dual-output synchronous boost converter of  claim 8  wherein the repeating sequence has the form first mode, second mode, third mode. 
     
     
       11. The dual-polarity dual-output synchronous boost converter of  claim 7  further comprising a feedback circuit that modulates the duration of the respective connections between the inductor, the input voltage, ground and the output nodes to control the voltage of the output nodes. 
     
     
       12. The dual-polarity dual-output synchronous boost converter of  claim 7  wherein the switching network is configured to provide a fourth mode in which the negative electrode of the inductor is connected to ground and the positive electrode of the inductor is connected in sequence to one or more of the fourth and fifth output nodes. 
     
     
       13. A method for operating a dual-polarity multi-output synchronous boost converter which includes an inductor and first, second, third, fourth and fifth output nodes, the method comprising:
 configuring a switching network so that the boost converter operates in a first mode in which a positive electrode of the inductor is connected to an input voltage and a negative electrode of the inductor is connected to ground; 
 configuring the switching network so that the boost converter operates in a second mode in which the negative electrode of the inductor is connected to ground and the positive electrode of the inductor is connected in sequence to each of the fourth and fifth output nodes; and 
 configuring the switching network so that the boost converter operates in a third mode in which the positive electrode of the inductor is connected to the input voltage and the negative electrode of the inductor is connected in sequence to each of the first, second and third output nodes. 
 
     
     
       14. The method of  claim 13  wherein the first, second and third modes are selected in a repeating sequence. 
     
     
       15. The method of  claim 14  wherein the repeating sequence has the form first mode, second mode, first mode, third mode. 
     
     
       16. The method as recited in  claim 14  wherein the repeating sequence has the form first mode, second mode, third mode. 
     
     
       17. The method of  claim 13  further comprising configuring the switching network so that the boost converter operates in a fourth mode in which the negative electrode of the inductor is connected to ground and the positive electrode of the inductor is connected in sequence to one or more of the fourth and fifth output nodes. 
     
     
       18. The method of  claim 17  further comprising modulating the duration of the respective connections between the inductor, the input voltage, ground and output nodes to control the voltage of the output nodes. 
     
     
       19. A dual-polarity multi-output synchronous boost converter comprising:
 an inductor; 
 a high-side switch and low-side switch connected in a series conduction path, the inductor being connected in the series conduction path between the high-side switch and the low-side switch; 
 a first node between the inductor and the low-side switch in the series conduction path, the first node being connected through a first positive-output synchronous rectifier switch to a first positive output terminal, through a second positive-output synchronous rectifier switch to a second positive output terminal, and through a third positive-output synchronous rectifier switch to a third positive output terminal, the first positive synchronous rectifier switch including a first MOSFET having a source-body short so as to create a first diode between a source and a drain of the first MOSFET; 
 a second node between the inductor and the high-side switch in the series conduction path, the second node being connected through a first negative-output synchronous rectifier switch to a first negative output terminal, and through a second negative-output synchronous rectifier switch to a second negative output terminal, the first negative-output synchronous rectifier switch including a second MOSFET having a source-body short so as to create a second diode between a source and a drain of the second MOSFET; and 
 a controller for controlling the on-time of the high-side and low-side switches being coupled to the high-side and low-side switches. 
 
     
     
       20. The dual-polarity multi-output synchronous boost converter of  claim 19  wherein the second positive-output synchronous rectifier switch includes a third MOSFET, the third positive-output synchronous rectifier switch includes a fourth MOSFET, and the second negative-output synchronous rectifier switch includes a fifth MOSFET. 
     
     
       21. The dual-polarity multi-output synchronous boost converter of  claim 20  wherein none of the third, fourth and fifth MOSFETs includes a source-body short. 
     
     
       22. The dual-polarity multi-output synchronous boost converter of  claim 20  wherein each of the third, fourth and fifth MOSFETS is connected to a respective body bias generator circuit, each body bias generator functioning to prevent any intrinsic diode in the MOSFET to which said body bias generator is connected from becoming forward-biased. 
     
     
       23. The dual-polarity multi-output synchronous boost converter of  claim 20  wherein a body of each of the third and fourth MOSFETs is respectively connected to the first positive output terminal. 
     
     
       24. The dual-polarity multi-output synchronous boost converter of  claim 20  wherein a body of the fifth MOSFET is connected to the second negative output terminal. 
     
     
       25. The dual-polarity multi-output synchronous boost converter of  claim 19  wherein each of the first, second, and third positive output terminals and each of the first and second negative output terminals are connected to the controller via respective feedback paths. 
     
     
       26. The dual-polarity multi-output synchronous boost converter of  claim 19  comprising only one single inductor.